Wednesday, September 30, 2020

Napolean Cat


We just learned about the Domestic Cat.

One type of domestic cat is a Napolean Cat or Minuet.

This is a cat with a normal sized body, but with short legs.

Even though they have short legs, they can still run jump and play just like any other cat.


(from: wikipedia - minuet cat)


Kid Facts - Blast from the past: Gastrodermis

Tuesday, September 29, 2020

Platelet


We just learned about the Red Blood Cell and the White Blood Cell.

The third type of blood cell is the Platelet, also called thrombocytes.

The name thrombocyte comes from the Greek words θρόμβος (thrombos) which means clot, and κύτος (kytos) which means cell.
Platelets get carried around in the veins and arteries, and if they see that there is some damage to the body, like a hole in the vein or artery then they will try and patch up the hole.

A bunch of platelets will work to connect to each other, and when they work to block up a hole like this it is called a clot.

So when you have a cut and are bleeding, the platelets come and make a blood clot and help fix up the cut.


(from: wikipedia - platelet)


Kid Facts - Blast from the past: Macula

Monday, September 28, 2020

Cirque Glacier


We just learned about the Piedmont Glacier.

Another kind of glacier is a Cirque Glacier.

This kind of glacier drains into a bowl shaped valley.


(from: wikipedia - cirque glacier)


Kid Facts - Blast from the past: Abatis

Sunday, September 27, 2020

Mirabilia Descripta


We just learned about the first English Bible, Wycliffe's Bible.

Another part of early Christianity from around the 1300s is the book Mirabilia Descripta.

When a Christian person named Jordanus of Severac went to India to explore and see what people believed in, he ran into some trouble, and was put into prison.

Later on he was let out, and traveled all over India writing about the way people lived, what they believed in, and all about the land and country.

He wrote it into a book he called Mirabilia Descripta which means something like Diary of Marvels.
His book was so well written at the time it was better than any other explorer from the west who traveled to India.

Because he wrote so well about it, other Christians were able to travel to India and help tell people about God and Jesus.


(from: wikipedia - jordanus)


Kid Facts - Blast from the past: Saint Ninian in Scotland

Saturday, September 26, 2020

Two Circus Women - Nadelman


We just learned about the Detroit Zoo's Rackham Fountain by Parducci.

Another famous American Sculpture is Two Circus Women by Elie Nadelman in New York in 1930.

In America in the 1900s a lot of sculptors came from Europe to get away from World War I, and to try and earn money by making sculptures.

Eli Nadelman was born in Poland in 1882, and became a famous sculptor there, even meeting with famous artists like Picasso.

In 1914 he left Poland and moved to America to get away from the war, and made many famous sculptures.
He also collected sculptures from other artists and made his own Museum of Folk Arts in Riverdale New York.

When the Great Depression hit, he had a very hard time making money, and when he had to sell his Museum and art studio many of his sculptures were destroyed.

A while after his death his art was rediscovered and many of his sculptures have been copied and remade around the country.

His sculpture of Two Circus Women was made in 1930, out of paper mache over plaster.
Plaster is kind of like cement, and paper mache is like paper covered in glue that is stuck on top of the plaster to decorate it.

Nadelman tried to make the circus performers look big and round, but not with very clear scultpure of their face.
It was not a very famous statue at the time, but later on it was copied and remade into a big marble statue and put at the famous New York State Theater.


(from: wikipedia - elie nadelman)


Kid Facts - Blast from the past: Were Jaguar Sculpture

Friday, September 25, 2020

Russian - Drinks


We counted to 900 in Russian! Wow!

Let's learn how to say some things to drink.

water вода (voda) - sounds like vah-dah 文A

milk молоко (moloko) - sounds like moh-loh-koh 文A

juice сок (sok) - sounds like soh-k 文A


russian language
(from: wikipedia - russian academy of sciences)

Norwegian: vann, melk, juice

Greek: water νερό (neró), milk γάλα (gála), juice χυμό (chymó)

ASL: water, milk, juice

Italian: acqua, latte, succo

German: Wasser, Milch, Saft

Spanish: agua, leche, jugo

French: eau, lait, jus

Thursday, September 24, 2020

Brake Shoe


We just learned about the Trailing Wheel.

Another part of a steam locomotive is the Brake Shoe.

When the train has to stop, there is a rounded piece of metal called the brake shoe that is pushed against the wheels to try and slow them down.

The scraping of the brake shoes on the metal wheel also helps clean the wheels, and after a while the brake shoes get worn down and need to be replaced with new ones.



(from: wikipedia - brake shoe)


Kid Facts - Blast from the past: Electromagnet

Wednesday, September 23, 2020

Domestic Cat


We just learned about the European Wildcat.

Another type of cat is the Domestic Cat, also called felis catus.

Domestic means being friendly in a house.
Cats have been friends and helpers to humans for thousands of years!

Scientists think cats and people first became friends because cats would help catch mice and rats that were pests in the house, and because they were friendly and liked to be petted and played with.

Just like there are a bunch of types of dogs out there, some people have named about 60 different types of cats.
Some types are like tabby, siamese or kinkalow!

There are are about 95 million pet cats in the USA.


(from: wikipedia - cat)


Kid Facts - Blast from the past: Mesoglea

Tuesday, September 22, 2020

Red Blood Cell


We just learned about the White Blood Cell.

Another type of blood cell is the Red Blood Cell, also called RBC, red cell, red blood corpuscle, haematid, erythroid cell, or erythrocyte.

Most of the weird science names come from other languages, like corpuscle comes from the Latin word "corpus" for body, haematid comes from the Greek word "hema" for blood, and erythrocyte comes from the Greek words "erythros" for red plus "kytos" for hollow vessel.

Remember there are three types of blood cells: White Blood Cells, Red Blood Cells, Platelets.

There are more red blood cells than the other two type of blood cells, with TRILLIONS of RBCs in the body.

The job of these blood cells is to take oxygen from the lungs to the body, going along the veins and arteries of the circulatory system.

They are shaped a little like a frisbee or a bowl, and they don't have a middle part called a nucleus like most other cells.
Just like the white blood cells, these are made in the bone marrow, and a grown up person makes over 2 million of these RBCs per second!
They go around the body and do their job for about 4 months, and then they get recycled back into the body and replaced by new ones.


(from: wikipedia - red blood cell)


Kid Facts - Blast from the past: Sclera

Monday, September 21, 2020

Piedmont Glacier


We just learned about what a Fjord is.

Another type of Glacier is a Piedmont Glacier.

Just like the other glaciers, when these melt the land around it can make them into a different shape.

If the valley where the glacier flows is a low flat plain, then it spreads out and looks sort of like a seashell or fan shape.


(from: wikipedia - glacier morphology)


Kid Facts - Blast from the past: Fujian Tulou

Sunday, September 20, 2020

Wycliffe's Bible


We just learned about the Divine Comedy - Paradiso.

Another part of early Christianity is Wycliffe's Bible.

When people found the old writings and letters that make up the Bible, they were in different languages like Hebrew, Greek or Aramaic.

The church put all of these together and translated them into Latin, and some other languages like Greek or Cyrillic.

The first time the Bible was written in English was when a priest named John Wycliffe worked to translate the whole Bible into English in 1395.

Wycliffe believed that people needed to be able to read the Bible in their own language, and not many people could speak or read Latin to understand the Bible readings in church.


(from: wikipedia - wycliffe's bible)


Kid Facts - Blast from the past: Latin Vulgate Bible

Saturday, September 19, 2020

Detroit Zoo Rackham Fountain - Parducci


We just learned about the National Shrine of the Little Flower by Chambellan.

Another famous American Sculputre is the Detroit Zoo Rackham Fountain by Corrado Parducci.

Corrado Parducci was born in Italy in 1900, and moved to the USA when he was 4 years old.

When he was young he went to art school, and at 17 he started working as an architectural sculptor.

There was a famous architect in Detroit named Albert Kahn who liked his art so much he asked him to come to Detroit, where he made some famous sculptures like the art on the Guardian Building in Detroit.

He also made other sculptures, like the Rackham Memorial Fountain in the Detroit Zoo.

When Parducci first came to Detroit, he only planned on staying for work for a little while, but because Detroit was so busy and successful he moved his whole family to Detroit and spent the rest of his life making sculptures all over hundreds of buildings in Michigan.


(from: wikipedia - detroit zoo)


(from: wikipedia - corrado parducci)


Kid Facts - Blast from the past: Aztec Sun Stone

Friday, September 18, 2020

Russian - Nine Hundred


We counted to 100 in Russian, let's keep going!

200 двести (dvesti) - sounds like d-veh-stee 文A

300 триста (trista) - sounds like t-dee-stah 文A

400 четыреста (chetyresta) - sounds like ch-eh-tee-dreh-stah 文A

500 пятьсот (pyat'sot) - sounds like pyat-soh-t 文A

600 Сшестьсотто (shest'sot) - sounds like sh-eh-st-soh-t 文A

700 семьсот (sem'sot) - sounds like sem-soh-t 文A

800 восемьсот (vosem'sot) - sounds like voh-sem-soh-t 文A

900 девятьсот (devyat'sot) - sounds like deh-v-yah-t-soh-t 文A


And here are some of the even bigger numbers!

And here are some of the even bigger numbers!

one thousand тысяча (tysyacha) - sounds like tee-s-yah-chah

one million один миллион (odin million) - sounds like oh-dee-n mee-lee-oh-n

one billion один миллиард (odin milliard) - sounds like oh-dee-n mee-lee-a-rd

one trillion один триллион (odin trillion) - sounds like oh-dee-n t-dee-lee-oh-n

one google один гугл (odin gugl) - sounds like oh-dee-n goo-ghel


russian language
(from: wikipedia - russian academy of sciences)

Norwegian: to hundre, tre hundre, fire hundre, fam hundre, seks hundre, syv hundre, åtte hundre, ni hundre

Greek: διακόσια (diakósia), τριακόσια (triakósia), τετρακόσια (tetrakósia), πεντακόσια (pentakósia), εξακόσια (exakósia), επτακόσια (eptakósia), οκτακόσια (oktakósia), εννιακόσια (enniakósia)

ASL: two hundred, three hundred, four hundred, five hundred, six hundred, seven hundred, eight hundred, nine hundred

Italian: duecento, trecento, quattrocento, cinquecento, seicento, settecento, ottocento, novecento

German: zweihundert, dreihundert, vierhundert, fünfhundert, sechshundert, siebenhundert, achthundert, neunhundert

Spanish: doscientos, trescientos, cuatrocientos, quinientos, seiscientos, sietecientos, ochocientos, novecientos

French: deux cent, trois cent, quatre cent, cinq cent, six cent, sept cent, huit cent, neuf cent

Thursday, September 17, 2020

Trailing Wheel


We just learned about the Smokebox at the front of the engine.

Another part of a steam locomotive is the Trailing Wheel.

Back behind all of the other big wheels that move the train is a smaller wheel.
This wheel has an axle bar going under the train that helps make the engine more stable especially where the fireman and engineer are standing.

Because it is not connected to any of the other gears that move the train along, this wheel is very strong and doesn't wiggle around so much.


(from: wikipedia - trailing wheel)


Kid Facts - Blast from the past: Windings

Wednesday, September 16, 2020

European Wildcat


We just learned about the African Wildcat.

Another type of wild cat is the European Wildcat, also called felis silvestris.

This type of cat is brown and grey, with some dark stripes on its face, body and tail.
These cats are about 2 feet long, and weigh about 17 pounds.
They live mostly in forests and mountains of eastern europe.

They look a lot like a normal house cat, but they are usually bigger and thicker with longer fur.

Sylvester the Cat from the Looney Tunes cartoons was named after the science name for this cat, felis silvestris.



(from: wikipedia - european wildcat)


Kid Facts - Blast from the past: Jellyfish - Epidermis

Tuesday, September 15, 2020

White Blood Cell


We just learned that there are three types of Blood Cell red blood cells, white blood cells and platelets.

Let's learn a little about White Blood Cells, also called WBCs, leukocytes or leucocytes.

These cells in the blood help fight against diseases or other bad things in the body.
This could be a type of virus or some kind of germs that got into the blood.

White blood cells are made in the bone marrow.
If there are a lot of white blood cells in the body, this can be a way for doctors to tell if someone is sick.
Looking at a liter of blood, if there are between 4,000 and 11,000 white blood cells then this is ok.
If there is a lot more or a lot less, then it is a sign the person is sick.

There are a lot of different types of white blood cells and they all have different jobs for fighting off anything that might be trying to hurt your body.


(from: wikipedia - white blood cell)


Kid Facts - Blast from the past: Optic Nerve

Monday, September 14, 2020

Fjord


We just learned about the Valley Glacier.

Another type of glacier movement is a Fjord.

When a glacier is melting and the water helps dig a deep valley in the ground, this is called a fjord.
A fjord is narrow, and has steep walls on either side with water in the middle.


(from: wikipedia - fjord)


Kid Facts - Blast from the past: Meurtrière

Sunday, September 13, 2020

Divine Comedy - Paradiso


We just learned about the Divine Comedy - Purgatorio.

Another part of the Divine Comedy book written in Early Christianity is Paradiso.

In this part of the story, Dante writes about what heaven might be like.

Long ago people didn't really know how the planets and stars worked, and a lot of people thought that the other planets and the sun went around the earth.
These days we know that the earth and other planets go around the sun, but in Dante's picture of heaven he thought the earth was the middle of our universe.

He wrote about 10 levels of heaven:
- Moon, Mercury, Venus, Sun, Mars, Jupiter, Saturn, Stars, Primum Mobile, Empyrean

Each higher level was better than the last one, and the Empyrean was the special holy perfect place where God lived.
The Primium Mobile was like a circle outside all of the planets that helped move the sun and stars, and this was where the angels lived.

Just like the other parts of this book, it was so popular that many people came to believe that this was what heaven really looked like.



(from: wikipedia - divine comedy)


Kid Facts - Blast from the past: The Great Persecution - Persia

Saturday, September 12, 2020

National Shrine of the Little Flower - Chambellan


We just learned about the Hugo Grotius - C. Paul Jennewein.

Another famous architecture sculpture is the National Shrine of the Little Flower by Rene Paul Chambellan, made in 1931 in Michigan.

The large limestone tower at this church has a 28 foot tall sculpture of Jesus on a cross. There are also smaller sculptures of the writers of the gospel, Matthew Mark Luke and John.
Below the crucifix are the last words that Jesus said before he died.

The sculptor Rene Paul Chambellan was born in New Jersey, and studied art in New York and Paris.

He spent most of his life as a sculptor of artwork that was part of buildings.


(from: wikipedia - national shrine of the little flower basilica)


Kid Facts - Blast from the past: La Mojarra Stela

Friday, September 11, 2020

Russian - One Hundred


We counted to 99 in Russian, let's keep going!

100 Сто (Sto) - sounds like stoh 文A

101 Сто один (Sto odin) - sounds like stoh oh-dee-n 文A

102 Сто два (Sto dva) - sounds like stoh d-vah 文A

103 Сто три (Sto tri) - sounds like stoh t-dee 文A

104 Сто четыре (Sto chetyre) - sounds like stoh cheh-tee-dee 文A

105 Сто пять (Sto pyat') - sounds like stoh pee-yah-t 文A

106 Сто шесть (Sto shest') - sounds like stoh sheh-s-t 文A

107 Сто семь (Sto sem') - sounds like stoh seh-m 文A

108 Сто восемь (Sto vosem') - sounds like stoh voh-seh-m 文A

109 Сто девять (Sto devyat') - sounds like stoh day-v-yah-t 文A


russian language
(from: wikipedia - russian academy of sciences)

Norwegian: ett hundre, ett hundre og en, ett hundre og to, ett hundre og tre, ett hundre og fire, ett hundre og fam, ett hundre og seks, ett hundre og syv, ett hundre og åtte, ett hundre og ni

Greek: εκατό (ekató), εκατόν ένα (ekatón éna), εκατόν δύο (ekatón dýo), εκατόν τρεις (ekatón treis), εκατόν τέσσερις (ekatón tésseris), εκατόν πέντε (ekatón pénte), εκατόν έξι (ekatón éxi), εκατόν επτά (ekatón eptá), εκατόν οκτώ (ekatón októ), εκατόν εννέα (ekatón ennéa)

ASL: One hundred, one hundred one, one hundred two, one hundred three, one hundred four, one hundred five, one hundred six, one hundred seven, one hundred eight, one hundred nine

Italian: cento, centodue, centotre, centoquattro, centocinque, centosei, centosette, sentotto, sentonove

German: einhundert, einhunderteins, einhundertzwei, einhundertdrei, einhundertvier, einhundertfünf, einhundertsechs, einhundertsieben, einhundertacht, einhundertneun

Spanish: ciento, ciento uno, ciento dos, ciento tres, ciento cuatro, ciento cinco, ciento seis, ciento siete, ciento ocho, ciento nueve

French: cent, cent, cent deux, cent trois, cent quatre, cent cinq, cent six, cent sept, cent huit

Thursday, September 10, 2020

Smokebox


We just learned about the Air Brakes.

Another part of a steam locomotive is the Smokebox.

This is the place on the front of the locomotive where the hot air and smoke goes to.

The coal burns up and the hot air goes through the boiler.
After that the hot air needs to be released, so it goes into the smokebox and then out the chimney.
Because the smoke is so dirty, it leaves a bunch of ashes in the smokebox, so the front of the train can be opened up and cleaned out when it gets too dirty.



(from: wikipedia - smokebox)


Kid Facts - Blast from the past: Stator

Wednesday, September 9, 2020

African Wildcat


We just learned about the Chinese Mountain Cat.

Another type of wild cat is the African Wildcat.

This cat lives in Africa & Asia.
It has grey or red fur, with black tufts on its ears, stripes on its face and legs, and a ringed tail.

The African Wildcat is a small cat, about 2 feet long and weighing about 10 pounds.
When it gets scared, it puffs its hair out to look bigger, but it usually hides out in the bushes.

We know that humans have kept cats as pets for a long time, and one time someone found ancient bones of an African Wildcat with a human, going back 9,500 years!



(from: wikipedia - african wildcat)


Kid Facts - Blast from the past: Jellyfish Bell

Tuesday, September 8, 2020

Blood Cell


We just learned about the Haematopoiesis.

The bone marrow that uses haematopoiesis makes Blood Cells, also called hematopoietic cells, hemocytes or hematocytes.

Remember we learned before that the Greek word for blood is hema, so that is why all of those other names start with hema.

Blood cells come in three types: Red blood cells, white blood cells and platelets.


(from: wikipedia - blood cell)


Kid Facts - Blast from the past: Lens

Monday, September 7, 2020

Valley Glacier


We just learned about the Outlet Glacier.

Another type of glacier is a Valley Glacier.

Sometimes when glaciers melt, the edge of the glacier is by a valley, a low place with a hill on either side.

So when the melted water flows out, the hills and the valley make sure the water flows in one way.


(from: wikipedia - glacier morphology)


Kid Facts - Blast from the past: Battery Tower

Sunday, September 6, 2020

Divine Comedy - Purgatorio


We just learned about the Divine Comedy and it's picture of the inferno.

Another part of that story is the Divine Comedy's picture of Purgatory.

Some Christians think that after you die if you believed in Jesus but did some bad things that you can go to a place between heaven and hell called purgatory and work your way up to heaven.

Other Christians don't agree and don't think this is a real place.

In the Divine Comedy, after the story goes through and talks about what hell looks like, it goes on to talk about what purgatory looks like.

In this place people were treated very badly, but not usually as badly as they were in the inferno hell.
They were forced to carry heavy weights, there was poisonous smoke and fire, and they were starving or blind.

If people made it through their suffering here for long enough they could go to heaven.
Many of the people and ideas in this picture of purgatory came from Greek mythology, so these weren't stories from the bible.
But because this book was so popular many people believed it was true.


(from: wikipedia - divine comedy)


Kid Facts - Blast from the past: Constantinople

Saturday, September 5, 2020

Hugo Grotius - C. Paul Jennewein


We just learned about the Pennsylvania Railroad World War II Memorial by Walker Hancock.

Another famous sculpture is the relief of Hugo Grotius by C. Paul Jennewein at the U.S. House of Representatives, made in 1950.

In the House building there are 23 different sculptures like this of famous people who worked in law and government.
Hugo Grotius was Dutch, and was a lawyer, a judge and a diplomat born in 1583.

The sculpture is made of marble and is a relief meaning there is a flat background and the face sticks out from it.

The artist Jennewein was born in Germany in 1890, and moved to the US when he was 17.
He was mostly famous for making architectural sculptures of people that were part of buildings.


(from: wikipedia - c. paul jennewein)


Kid Facts - Blast from the past: Double Headed Serpent

Friday, September 4, 2020

Russian - Counting to Ninety Nine


We counted to 89 in Russian, let's keep going!

90 девяносто (devyanosto) - sounds like deh-v-yah-noh-stoh 文A

91 девяносто один (devyanosto odin) - sounds like deh-v-yah-noh-stoh oh-dee-n 文A

92 девяносто два (devyanosto dva) - sounds like deh-v-yah-noh-stoh d-vah 文A

93 девяносто три (devyanosto tri) - sounds like deh-v-yah-noh-stoh t-dee 文A

94 девяносто четыре (devyanosto chetyre) - sounds like deh-v-yah-noh-stoh cheh-tee-dee 文A

95 девяносто пять (devyanosto pyat') - sounds like deh-v-yah-noh-stoh pee-yah-t 文A

96 девяносто шесть (devyanosto shest') - sounds like deh-v-yah-noh-stoh sheh-s-t 文A

97 девяносто семь (devyanosto sem') - sounds like deh-v-yah-noh-stoh seh-m 文A

98 девяносто восемь (devyanosto vosem') - sounds like deh-v-yah-noh-stoh voh-seh-m 文A

99 девяносто девять (devyanosto devyat') - sounds like deh-v-yah-noh-stoh day-v-yah-t 文A


russian language
(from: wikipedia - russian academy of sciences)

Norwegian: nitti, nittien, nittito, nittitre, nittifire, nittifam, nittiseks, nittisyv, nittiåtte, nittini

Greek: ενενήντα (enenínta), ενενήντα ένα (enenínta éna), ενενήντα δύο (enenínta dýo), ενενήντα τρεις (enenínta treis), ενενήντα τέσσερις (enenínta tésseris), ενενήντα πέντε (enenínta pénte), ενενήντα έξι (enenínta éxi), ενενήντα επτά (enenínta eptá), ενενήντα οκτώ (enenínta októ), ενενήντα εννέα (enenínta ennéa)

ASL: Ninety, ninety one, ninety two, ninety three, ninety four, ninety five, ninety six, ninety seven, ninety eight, ninety nine

Italian: novanta, novantuno, novantadoue, novantatre, novantaquattro, novantacinque, novantasei, novantasette, novantotto, novantanove

German: neunzig, einundneunzig, zweiundneunzig, dreiundneunzig, vierundneunzig, fünfundneunzig, sechsundneunzig, siebenundneunzig, achtundneunzig, neunundneunzig

Spanish: noventa, noventa y uno, noventa y dos, noventa y tres, noventa y cuatro, noventa y cinco, noventa y seis, noventa y siete, noventa y ocho, noventa y nueve

French: quatre-vingts dix, quatre-vingt onze, quatre-vingt douze, quatre-vingt treize, quatre-vingt quatorze, quatre-vingt quinze, quatre-vingt seize, quatre-vingt dix sept, quatre-vingt dix huit, quatre-vingt dix neuf

Thursday, September 3, 2020

Air Brakes


We just learned about the Sand Dome.

Another part of steam locomotives is the Air Brakes.

When the engineer wants to stop the train, he pulls a lever to use the brakes.
The lever opens up something called an air reservoir which is a place where high pressured air is stored.
It is kind of like a really tight balloon filled with air, and opening it up causes the air to come blowing out.

The air goes through some tubes to get to a piece of metal called the brake shoe, and the air pressure pushes the metal brake shoe up against the wheel to stop the train.



(from: wikipedia - railway air brake)


Kid Facts - Blast from the past: Rotor

Wednesday, September 2, 2020

Chinese Mountain Cat


We just learned about the Sand Cat.

Another type of wild cat is the Chinese Mountain Cat, also called the Chinese desert cat or felis bieti.

This type of cat lives in western China, and there are less than 10,000 of them left in the world.
These cats have sandy colored fur with some dark stripes on their face and legs, and black tipped ears.

They are about 3 feet long, and weigh around 20 pounds.
Their tail is big and bushy and has black rings on it.


(from: wikipedia - chinese mountain cat)


Kid Facts - Blast from the past: Marrus Orthocanna

Tuesday, September 1, 2020

Haematopoiesis


We just learned about the Bone Marrow.

The bone marrow that makes blood cells is part of Haematopoiesis which comes from the Greek words αἷμα (aima) "blood" and ποιεῖν (poieín) "to make", so it means "to make blood".

A normal human body can make from one hundred billion to a trillion blood cells every day!


(from: wikipedia - haematopoiesis)


Kid Facts - Blast from the past: Retina